Effect of spatially varying material properties on the post-buckling behaviour of composite panels utilising geodesic stochastic fields

The post-buckling behaviour of panels can be very sensitive to imperfections
or variations in materials or geometry. This paper presents an
ecient numerical model to calculate the eects of material stiffness
variations on the non-linear response of a structure. This is done by
first defining a geodesic mesh on which a unit variance random field is
generated. This field uses the true geodesic distance on the structure to
calculate how points in the field should be correlated. The fields generated
are projected onto a 3D structural mesh which is used for assembly and
post-processing of the structural model. The structural model, based on
the Unified Formulation is capable of accurate non-linear calculations of
both straight and curved elements. Baseline results generated using the
implementation are compared to those in literature, and verified using
Abaqus. Random material variations are then applied to the structure
in a Monte Carlo analysis. The analyses show that the local variation
of stiffness can have a variety of effects on the non-linear response of
structures. Aside from the change of mean stiffness causing a change in
bifurcation or limit point load, the different stiffness distributions can
affect and trigger competing buckling modes and post-buckling modes
and affect their corresponding post-buckling load-deflection paths.